We all scream for ice cream. In diapers? And now a complex multilayered experiment that touches on micro economics, sociology and psychology. It's about the power of free. We serve chocolate ice cream out of a diaper. So it looks like poop! So, it's a steamy summer's day in brooklyn and we're in the park, giving away free ice cream. Pretending our cameras are shooting a promo video for a revolutionary new product. Well that's our story. Step right up. Get your free ice cream. Who could possibly say no to free ice cream on a hot day, right? We're doing a promotion here. We're giving out free ice cream. Would you like some? But there's a catch. We're serving the ice cream in diapers. And these aren't just any diapers. We're telling people these are recycled diapers. Yep. Pre-used, previously pooped in, recycled. Testing the power of free to its very limits. I don't think anyone's going to be screaming for this today. Okay, this sounds ridiculous and juvenile, but there's science. It's called the zero price effect, also known as the power of free. When the price tag is zero, rational behavior goes out the window. Well, so the theory goes. Any toppings for you, ma'am? Yeah, a little hot fudge. Hot fudge. Just a little. Yeah, well we're doing our little promo video here today and we're going hopefully get into some stores. Thank you very much. So, people don't care that the diaper is recycled. Not one lick. So clean, you can eat out of them. So clean, you can eat out of them. As you can see diagram they're taken out of landfills, they go through the cleansing process and out fresh new, so clean you can eat out of them. Cool! They just want free ice cream. Don't worry. The diapers aren't actually recycled. They are brand new, and we lined them with plastic. We're just making up the recycled bit to see if we can find the breaking point of the power of free. We recycle stuff out of everything else. What's the difference? The difference? This is a once-used diaper. So this is a recycled diaper. Eww. Okay, so she's totally grossed out. Now it's totally safe to eat out of. And that's what everyone's been doing. Oh my gosh, you're going to eat the ice cream out of the diaper? Wait a second. Is that what's going on? Totally safe, non toxic. Eww. What does that look like to you? Poop. But the power of free is hard at work. Would you like some fudge for your diaper? Sure. What was that face? This is weird! It's a diaper! It's all squishy! Ew! I mean, it shouldn't taste any different. Yeah, it's not bad. Scott's graphic description is no match for the zero price effect. Which says, no matter what you pile on one side of the scale, free ice cream wins. Diaper-licious. Really? She went from grossed out to spoon in mouth in two minutes and 37 seconds. That's the power of free. Are you serving it in a diaper? We're serving it, yeah. And then, finally, our first refusal. For real? Yeah, to show it's so clean you can eat out of it. So clean you can eat out of it. No, I can't do it. I've changed a lot of diapers. And the association is so strong for me. You like had that memory. Some sense memory there. Yep. So had we finally found the limit? Are parents with fresh, first-hand experience of changing dirty diapers, are they incapable of being blinded by the power of free? Oh no. It's so clean you'll feed your kid out of it. All right, this demonstration may have been a bit infantile. But if parents are feeding free ice cream to their children from what they think are recycled diapers, I think we've proved our point. Wyfft. So clean you can eat out of

This transcript has been automatically generated and may not be 100% accurate.

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